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4564e63f80
We need to restrict *all* the control fds that qemu opens. Looking in /proc/PID/fd shows there are many; their allocation seems scattered throughout Xen support code in qemu. We must postpone the restrict call until roughly the same time as qemu changes its uid, chroots (if applicable), and so on. There doesn't seem to be an appropriate hook already. The RunState change hook fires at different times depending on exactly what mode qemu is operating in. And it appears that no-one but the Xen code wants a hook at this phase of execution. So, introduce a bare call to a new function xen_setup_post, just before os_setup_post. Also provide the appropriate stub for when Xen compilation is disabled. We do the restriction before rather than after os_setup_post, because xen_restrict may need to open /dev/null, and os_setup_post might have called chroot. Currently this does not work with migration, because when running as the Xen device model qemu needs to signal to the toolstack that it is ready. It currently does this using xenstore, and for incoming migration (but not for ordinary startup) that happens after os_setup_post. It is correct that this happens late: we want the incoming migration stream to be processed by a restricted qemu. The fix for this will be to do the startup notification a different way, without using xenstore. (QMP is probably a reasonable choice.) So for now this restriction feature cannot be used in conjunction with migration. (Note that this is not a regression in this patch, because previously the -xen-restrict-domid call was, in fact, simply ineffective!) We will revisit this in the Xen 4.11 release cycle. Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com> CC: Paolo Bonzini <pbonzini@redhat.com> (maintainer:X86) CC: Richard Henderson <rth@twiddle.net> (maintainer:X86) CC: Eduardo Habkost <ehabkost@redhat.com> (maintainer:X86) CC: Michael S. Tsirkin <mst@redhat.com> (supporter:PC) Acked-by: Anthony PERARD <anthony.perard@citrix.com> |
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accel | ||
audio | ||
backends | ||
block | ||
bsd-user | ||
capstone@22ead3e0bf | ||
chardev | ||
contrib | ||
crypto | ||
default-configs | ||
disas | ||
docs | ||
dtc@e54388015a | ||
fpu | ||
fsdev | ||
gdb-xml | ||
hw | ||
include | ||
io | ||
libdecnumber | ||
linux-headers | ||
linux-user | ||
migration | ||
nbd | ||
net | ||
pc-bios | ||
po | ||
qapi | ||
qga | ||
qobject | ||
qom | ||
replay | ||
roms | ||
scripts | ||
scsi | ||
slirp | ||
stubs | ||
target | ||
tcg | ||
tests | ||
trace | ||
ui | ||
util | ||
.dir-locals.el | ||
.editorconfig | ||
.exrc | ||
.gdbinit | ||
.gitignore | ||
.gitmodules | ||
.gitpublish | ||
.mailmap | ||
.shippable.yml | ||
.travis.yml | ||
arch_init.c | ||
balloon.c | ||
block.c | ||
blockdev-nbd.c | ||
blockdev.c | ||
blockjob.c | ||
bootdevice.c | ||
bt-host.c | ||
bt-vhci.c | ||
Changelog | ||
CODING_STYLE | ||
configure | ||
COPYING | ||
COPYING.LIB | ||
COPYING.PYTHON | ||
cpus-common.c | ||
cpus.c | ||
device-hotplug.c | ||
device_tree.c | ||
disas.c | ||
dma-helpers.c | ||
dump.c | ||
exec.c | ||
gdbstub.c | ||
HACKING | ||
hmp-commands-info.hx | ||
hmp-commands.hx | ||
hmp.c | ||
hmp.h | ||
ioport.c | ||
iothread.c | ||
LICENSE | ||
MAINTAINERS | ||
Makefile | ||
Makefile.objs | ||
Makefile.target | ||
memory.c | ||
memory_ldst.inc.c | ||
memory_mapping.c | ||
module-common.c | ||
monitor.c | ||
numa.c | ||
os-posix.c | ||
os-win32.c | ||
qdev-monitor.c | ||
qdict-test-data.txt | ||
qemu-bridge-helper.c | ||
qemu-doc.texi | ||
qemu-ga.texi | ||
qemu-img-cmds.hx | ||
qemu-img.c | ||
qemu-img.texi | ||
qemu-io-cmds.c | ||
qemu-io.c | ||
qemu-keymap.c | ||
qemu-nbd.c | ||
qemu-nbd.texi | ||
qemu-option-trace.texi | ||
qemu-options-wrapper.h | ||
qemu-options.h | ||
qemu-options.hx | ||
qemu-seccomp.c | ||
qemu-tech.texi | ||
qemu.nsi | ||
qemu.sasl | ||
qmp.c | ||
qtest.c | ||
README | ||
replication.c | ||
replication.h | ||
rules.mak | ||
thunk.c | ||
tpm.c | ||
trace-events | ||
VERSION | ||
version.rc | ||
vl.c |
QEMU README =========== QEMU is a generic and open source machine & userspace emulator and virtualizer. QEMU is capable of emulating a complete machine in software without any need for hardware virtualization support. By using dynamic translation, it achieves very good performance. QEMU can also integrate with the Xen and KVM hypervisors to provide emulated hardware while allowing the hypervisor to manage the CPU. With hypervisor support, QEMU can achieve near native performance for CPUs. When QEMU emulates CPUs directly it is capable of running operating systems made for one machine (e.g. an ARMv7 board) on a different machine (e.g. an x86_64 PC board). QEMU is also capable of providing userspace API virtualization for Linux and BSD kernel interfaces. This allows binaries compiled against one architecture ABI (e.g. the Linux PPC64 ABI) to be run on a host using a different architecture ABI (e.g. the Linux x86_64 ABI). This does not involve any hardware emulation, simply CPU and syscall emulation. QEMU aims to fit into a variety of use cases. It can be invoked directly by users wishing to have full control over its behaviour and settings. It also aims to facilitate integration into higher level management layers, by providing a stable command line interface and monitor API. It is commonly invoked indirectly via the libvirt library when using open source applications such as oVirt, OpenStack and virt-manager. QEMU as a whole is released under the GNU General Public License, version 2. For full licensing details, consult the LICENSE file. Building ======== QEMU is multi-platform software intended to be buildable on all modern Linux platforms, OS-X, Win32 (via the Mingw64 toolchain) and a variety of other UNIX targets. The simple steps to build QEMU are: mkdir build cd build ../configure make Additional information can also be found online via the QEMU website: https://qemu.org/Hosts/Linux https://qemu.org/Hosts/Mac https://qemu.org/Hosts/W32 Submitting patches ================== The QEMU source code is maintained under the GIT version control system. git clone git://git.qemu.org/qemu.git When submitting patches, one common approach is to use 'git format-patch' and/or 'git send-email' to format & send the mail to the qemu-devel@nongnu.org mailing list. All patches submitted must contain a 'Signed-off-by' line from the author. Patches should follow the guidelines set out in the HACKING and CODING_STYLE files. Additional information on submitting patches can be found online via the QEMU website https://qemu.org/Contribute/SubmitAPatch https://qemu.org/Contribute/TrivialPatches The QEMU website is also maintained under source control. git clone git://git.qemu.org/qemu-web.git https://www.qemu.org/2017/02/04/the-new-qemu-website-is-up/ A 'git-publish' utility was created to make above process less cumbersome, and is highly recommended for making regular contributions, or even just for sending consecutive patch series revisions. It also requires a working 'git send-email' setup, and by default doesn't automate everything, so you may want to go through the above steps manually for once. For installation instructions, please go to https://github.com/stefanha/git-publish The workflow with 'git-publish' is: $ git checkout master -b my-feature $ # work on new commits, add your 'Signed-off-by' lines to each $ git publish Your patch series will be sent and tagged as my-feature-v1 if you need to refer back to it in the future. Sending v2: $ git checkout my-feature # same topic branch $ # making changes to the commits (using 'git rebase', for example) $ git publish Your patch series will be sent with 'v2' tag in the subject and the git tip will be tagged as my-feature-v2. Bug reporting ============= The QEMU project uses Launchpad as its primary upstream bug tracker. Bugs found when running code built from QEMU git or upstream released sources should be reported via: https://bugs.launchpad.net/qemu/ If using QEMU via an operating system vendor pre-built binary package, it is preferable to report bugs to the vendor's own bug tracker first. If the bug is also known to affect latest upstream code, it can also be reported via launchpad. For additional information on bug reporting consult: https://qemu.org/Contribute/ReportABug Contact ======= The QEMU community can be contacted in a number of ways, with the two main methods being email and IRC - qemu-devel@nongnu.org https://lists.nongnu.org/mailman/listinfo/qemu-devel - #qemu on irc.oftc.net Information on additional methods of contacting the community can be found online via the QEMU website: https://qemu.org/Contribute/StartHere -- End